Re: Does this sound like a fuel pump problem or ignition failure?

[steveb@newkla.kla.com (Steven Buchholz)]

Anthony Chan <chan@seattleu.edu> wrote:
> Does anyone know if there is a screen inside the fuel tank of an 85' 5000s?
> 
> My 5000s just started with this weird problem last weekend, it will suddenly 
> lost power and then stall completely but you can start it right up. It usually
> happen after at least one to two hours of driving. The fuel pump was replaced
> 
	<Background info snipped to save bandwidth>
> 
> It cut out 5 times on the freeway last weekend, it was fun diving for 
> shoulders! :P 
> 
> Does anyone have any idea what causing the problem? 

I don't think the 5k has a screen inside the tank, but I have heard that some
fuel pumps have inlet screens that can get clogged.  I remember seeing an 
Audi Tech Bulletin that talked about simply hacking out the screen.  I would 
doubt that this is your problem though because I would think that you would 
have noticed a problem in fuel pressure or volume tests that were done.  

You didn't say if the tach went dead immediately or any other ignition type 
symptoms.  I did see a car that had an intermittent in the ign coil where 
the tach would go from normal (~3500) to 0000 right before you noticed that 
the engine lost power.  The problem did seem to have some sort of temperature
dependency as well ... the failure did not occur on short trips.  

Your problem sounds similar to one I had with the '88 5k earlier this year.
The problem degraded over time to the point where it got harder to start at 
times and would lose power under acceleration on hills and such.  In this 
case the problem was the coil wire had broken in the connection at the dis-
tributor cap.  Things got so burned up inside there that I had to buy  a new 
cap with the wire.

Steve Buchholz
s_buchho@kla.com